MARCO POLO AND THE DISCOVERY OF THE WORLD, by John Larner. New Haven: Yale University Press, 1999, 250 pp., with plates (14) and maps, unpriced.

In 1271, a mere 17 years old, Marco Polo left Venice in company with his uncle and several other merchants. Twenty-four years later, in 1295, he returned, now a mature 41.

Along with merchandise and money, he came back with extraordinary memories of his long trip through Asia, one that culminated with his years at the court of China. With help from others, he fashioned these into his famous book of travels.

The original manuscript of this work does not survive. Instead there are the texts of some 150 "editions," of which it has been said that no two are exactly the same.

Nonetheless, the influence of the work was enormous. It offered Europe a portrait of a world that was almost entirely new -- the lands east of Badakhshan and Karakorum, the provinces of China, and the astonishing empire of the Great Khan. What was generally believed about the geography of the world was permanently changed by this young Italian merchant.

At the same time, the work was -- and continues to be -- challenged. Some scholars hold that it was never really believed at all, that it was always held to be romance or fable. Others, more recently, have come to believe that Marco never went to China. Several more hold that his was precolonial exoticism, that -- presumably in the Genoa jail where he is assumed to have written his account -- he was the first Orientalist, appropriating other cultures for his own fell purposes.

It was perhaps this dissent that inspired John Larner, professor emeritus at Glasgow University, to review the material making up the scholarly mess and to produce this elegant and reasoned book. In it, he confronts the various charges, considers them, then places each in the context of Polo's culture, his life and the later adventures of his remarkable book.

That the travels were early thought to be fiction was perhaps due to his collaborator's talents in writing courtly romances. Larner indicates this by retranslating passages, thus retaining the fanciful style that later translations flattened. In the process, the picture of the two of them scribbling away in chains is corrected. "Prison" was what we might now call house arrest. Polo and his collaborator were simply not allowed the freedom of Genoa.

Those who now maintain that Polo never went to China because he did not, for example, mention the Great Wall or foot-binding are silenced by Larner's observations that the latter had not yet begun and that the former had fallen down. What we now believe to be the original Great Wall is in large part, at least around the capital, a 16th-century reconstruction.

The author's aim throughout, however, is not to refute other scholars, but to find out just what kind of account Polo wrote, and why. As John Critchley has put it, "Even Polo's proven lies are of the sort which only someone who knew what he was talking about could have told."

His two mentions of Japan, for example, can "without exaggeration be described as nonsense." Walls two fingers thick with fine gold, pearls just everywhere, eight Japanese prisoners who could not be beheaded because of magical properties -- they had instead to be clubbed to death. Yet, as Larner adds: "It was immensely fruitful nonsense."

It informed Christopher Columbus, for example (to just what extent it did is the subject of one of the most interesting chapters of this book); until his dying day, Columbus thought that in Cuba he had discovered Japan.

Polo himself maintained his truthfulness. When he was dying, at the age of 69 in 1324, his confessor remembered that "because there are many great and strange things in his book which are reckoned past all credence, he was asked by his friends on his deathbed to correct it by removing everything that went beyond the facts. To which his reply was that he had not told one half of what he had actually seen!"